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Is this sacriligious?
http://w-ww.luthiersforum.com/forum/viewtopic.php?f=10101&t=51983		 Page 1 of 1
Author:  Tai Fu [ Wed May 29, 2019 8:26 am ]
Post subject:  Is this sacriligious?
I went and bit the bullet and bought a bandsaw. I can't build any guitars without it, and a milling machine makes poor saws (I can probably install a slitting saw on it but it will not resaw wood billets).

I got myself a 14" welded steel bandsaw with a stand... it has a cutting height of around 10 inches. Kinda like a cast iron 14" bandsaw with riser blocks. It costs me 600 dollars total. While I'm at it I bought a small no name laminate trimmer so I can do bindings and other stuff (stuff that won't fit in a mill).

It came with the router, a fixed base, a tilting base (for binding work), and a set of router bits... I took one bit and did this:

Image

Used it in my mill to roundover aluminum.

Anyone ever tried cutting fancy profiles with a mill using router bits?
Author:  SteveSmith [ Wed May 29, 2019 8:57 am ]
Post subject:  Re: Is this sacriligious?
I use wood tools to cut aluminum quite often, it's a common practice.
Author:  jfmckenna [ Wed May 29, 2019 10:36 am ]
Post subject:  Re: Is this sacriligious?
Hmmmm. I never would have thought to do that but so it goes.
Author:  Chris Ensor [ Wed May 29, 2019 10:41 am ]
Post subject:  Re: Is this sacriligious?
Bit is fine. But is it being held in a drill chuck?!
Author:  Tai Fu [ Wed May 29, 2019 10:51 am ]
Post subject:  Re: Is this sacriligious?
it is, though when I hold an end mill this way it chatters a bit more than if I use ER40 collets. I was just a bit too lazy to change to an ER collet since I just wanted to see if a router bit would cut in a mill... the RPM is after all quite a bit lower. I only set the power feed slower to reduce the cutting force.

This drill chuck grips very tightly however, never had it slip before.
Author:  Colin North [ Wed May 29, 2019 1:34 pm ]
Post subject:  Re: Is this sacriligious?
I ran a 10mm straight router bit mounted in a laminate trimmer into an aluminium plate quite quickly. (accidentally)
Made a reasonable job of cutting the aluminium, but didn't do the bit any good, had to bin it.
Author:  Tai Fu [ Wed May 29, 2019 1:55 pm ]
Post subject:  Re: Is this sacriligious?
Well, you do have to realize that a laminate trimmer held by hand lacks the rigidity to cut aluminum other than a skim (.01") cut anyways. That is what ruined your bit. A bridgeport mill on the other hand is quite rigid and when fed on a mill table (not by hand where the cut can chatter) will not hurt the cutter... Routers aren't meant to cut metal and has very little rigidity, only enough to cut wood with (also your hand has no rigidity as well, mount the laminate trimmer on a very rigid frame and it will cut aluminum fairly well too)

I found my carbide end mills to last much longer cutting even steel on my mill compared to the mini mill I used to use (they would dull rather quickly). I think it's because the machine lacked rigidity and so the bit generated quite a bit of runout, meaning one flute cut more than another and that of course chips the carbide.

Even the VMC my neighbor use he doesn't cut more than 1/8" at a time, even though his machines weight 3 tons (mine only weight one ton). The end mills lasts forever plowing through aluminum at 1000mm/minute feed rate.
Author:  Colin North [ Wed May 29, 2019 2:17 pm ]
Post subject:  Re: Is this sacriligious?
Trimmer was held pretty solid in a jig, in a vice, although obviously a milling machine is more has less movement.
I think that the 30.000 RPM and rate of cut had more to do with the damaged bit.
Author:  Burton LeGeyt [ Thu May 30, 2019 9:27 am ]
Post subject:  Re: Is this sacriligious?
A router bit will cut aluminum just fine. Light cuts, a sharp bit, and the correct alloy of aluminum (i.e not too gummy) helps a lot. A mill is certainly more rigid but I have done it handheld with a fence and it works fine. Be careful, of course, but it is very possible.

Using a drill chuck to hold it is a very bad idea- The issue isn't that it won't hold the bit securely it is that the chuck itself is mounted to an arbor by friction only. Not an issue when you are drilling and reinforcing the friction fit every time. With side pressure, though, it wouldn't be pretty if it let go.

A side note- I have also successfully shaped cast iron with a router bit in a laminate trimmer. It isn't nearly as hard on cutting tools as steel and works surprisingly well. When I needed to open up the throat on my bandsaw I made a plywood form and used a short pattern bit to make a new ledge in the iron. Small cuts, but the trimmer didn't complain at all. bit looked fine too. I wouldn't go after a brand new casting like this, but small modifications to existing parts is something I would attempt again if I couldn't easily get it on the mill.
Author:  Tai Fu [ Thu May 30, 2019 9:43 am ]
Post subject:  Re: Is this sacriligious?
The chuck on my mill won't fall off. It's a NT40-APU16 one piece chuck, meaning the entire chuck unit is machined into the NT40 arbor and absolutely WILL NOT fall off. It wasn't a JT6 type deal where you had to press the chuck into it. Thing weights a ton too (the chuck unit that is).

Image

There appears to be a large socket cap screw inside the drawbar thread hole... I think the parts of the chuck probably mounts from that.

Needless to say it is very solidly constructed and I've used it to hold milling cutters without any issues, it's just not as rigid as using a ER40 collet.
Author:  Burton LeGeyt [ Thu May 30, 2019 9:58 am ]
Post subject:  Re: Is this sacriligious?
Ahh- Yes that is very different. Cool!
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